Myself I would keep the Elellbrock and run the manifolds on the street.

 

Depends on usage. On the street the Edelbrock is fine but like the Holley some versions are better than others the Thunder AVS and AVS2 are more flexible to tune than the Performer AFB. Neither like a hot intake manifold nor fuel pressure beyond 6psi. They tune AFR differently than the Holley the Edelbrock use different combinations of jet sizes and metering rod sizes and different strength springs to control where the metering rod is positioned in the jet for cruise and power. Edelbrock has a great tuning manual in paper and on line. The Holley is a little less heat or fuel pressure sensitive it tunes AFR buy combinations of fuel metering jet sizes and those of air correction assuming youre buying a higher end model. The power mixture is controlled by a on/off vacuum valve that similar to the Edelbrock metering rod piston operated off manifold vacuum against a spring, the Holley valves come in different vacuum sensitivities that control switching on/off. As far as I know Holley doesn’t furnish much tuning info for the average hobbiest, this you lean by cut and try or take it to one of the several professional tuners. Both carbs brands have been around in their current configurations in one detail form or another for about 65 years.

For street cruising rams horns are fine if however squeezing every ounce of power is your concern then long tube headers are the ticket. Depending on brand and exact vehicle installation these can go from simple to miserable. And spark plug R&R is a substantial PIA with most anybody’s headers.

Bogie

 

Id go with headers on just about any hotrod unless old school look is the goal. Or in the case of an odd ball motor swap that would require custom built headers and you arent capable of making them,....but even then Id go block huggers.
As far as carb I like my holleys but now that Ive got a handle on the AFB its not too bad and easier to tune the enrichment.

 

Agree with Bogie. Lots of 'speed' mods are only effective at high RPM WOT. Yeah some intakes and headers can help low end torque but if you're an automatic you might never notice it.
I actually had trouble tuning the Edelbrock, and the car was pretty happy when I switched to a Holley. Just my experience. 71 SBC

 

If they are the 2.5" versions with straight down dumps, they are perfectly fine on a mild street 350. Back in the day I temporarily replaced some crappy headers (because they hung down too low and the coating was blistering) with 2" truck rams horns. Any difference in throttle response and acceleration was not noticeable on my butt dyno. Engine was a mild 383 built for mid range torque.

As for Edelbrock vs. Holley, it depends on the type of each carb as well as manifold vacuum. About the guy who told you to get rid of the Edelbrock: You should ask him for specific reasons, and then which Holley carb he would recommend. Wouldn't surprise me if he says "750", which seems to be the standard vague answer these days by less knowledeable "mechanics". Also ask him about the 4150 series vs. 4160, and about vacuum secondaries vs. mechnaical, and about changeable air bleeds.

 

Tuning the Edelbrock its fuel jet sizes, metering rod sizes, metering piston springs and for the AVS type (Thunder) original and -2 the flapper valve control spring. There is no adjustment on the AFB (Performer) version.

For the Holley there is a host of fuel jets besides main metering, there is accelerating pump, power enrichment with jets and different control valves, then idle just for fuel. Then a bunch of air correction jets on the idle and main metering circuits. Plus there are selectable secondary springs on the vacuum secondaries to trim their tip in. And people talk about how complicated QJets are to work on, give me a break!

Bogie